Managing Environment: Sustainability: The Water Challenge

March 1, 2010
“…Water, water, everywhere. Nor any drop to drink.” These two famous lines are from “The Rime of the Ancient Mariner,” written by Samuel Taylor Coleridge (1798). They summarize, in large part, the concern for water.

In my last article ("Sustainability: The EHS Challenge," EHS Today, January 2010), I discussed the background on the concept of sustainability and the Bruntland Report, where sustainability was defined as, “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

I described sustainability as being analogous to a three-legged stool, with the legs being social aspects, economic aspects and the environmental aspects. In the environmental area, I described three broad areas of concern. These were energy and global warming (discussed in the last article), water and waste. In this article, I will provide an overview of the key issues for water as they relate to sustainability.

Water, as a generalization, neither is created nor destroyed, unlike energy and greenhouse gases. Water endlessly is recycled (which is known commonly as the water cycle). The problem with water is twofold. First, there is the issue of distribution, and second, the issue of contamination. Water is abundant (70 percent to 75 percent of the earth's surface), but potable water is not. Only approximately 1 percent of the earth's water is potable, with 97 percent salty and 2 percent locked in ice formations.


As everyone recognizes, there are locations where fresh water is abundant (e.g., the Great Lakes Region) and locations where fresh water is scarce (southwestern United States) to extremely scarce (deserts). Globally, there are a great many areas that have water scarcities, especially sub-Saharan Africa and South Asia.

Even where fresh water is present, much of the world lacks adequate sanitation to protect this water. WaterAid estimated in 2005 that approximately 20 percent of the world population (1.1 billion persons) lacked access to safe drinking water.

The United States has one of the best water distribution systems in the world. Nevertheless, there still are significant problems even with our modern technology. Droughts, water restrictions and water rationing are common to many areas of the United States. Even in areas drenched with fresh water, such as South Florida, water use restrictions now are commonplace.


The second issue related to water is contamination. Water used but not containing human waste or other hazardous contaminants is referred to as grey water, while water contaminated with human waste or agricultural and industrial waste is called black water. Fresh, uncontaminated water has been called “blue water.”

Grey water can be reused for many purposes (e.g., irrigation, additional cleaning, etc.), while black water requires treatment. From a practical viewpoint, one must pay for water drawn from a source and also for treatment after use. This practicality provides the financial incentive for conservation.

Ecologically, one would be expected (as a good citizen) to conserve blue water and to reduce black water. For most governmental and non-governmental organizations (NGOs), water conservation would be expected whether blue water is abundant or not. One could argue this point, but it is somewhat more complex on a global basis than it otherwise appears.


A few years ago, Arjen Y. Hoekstra, a professor in the Netherlands, developed the concept of the water footprint (analogous to the carbon footprint). He also developed the concept of virtual water trading, where his organization tracks the export and import of water as found in products or utilized for services. For example, a kilo of fine Japanese Kobe beef would be equivalent to 16,000 liters of water for the beef, plus all the transport and import activities. Using this approach, dinner for two, excluding drinks and other food in an excellent restaurant, is the equivalent to the water used by a family of four for half a year in areas of water scarcity.

The other end of the spectrum is (fortunately) beer, which only is estimated to take 200 liters per liter to produce. This becomes significant when countries or locations with water scarcity export products with large water footprints or conversely when the “have” countries import high water footprint products (e.g., fine Egyptian cotton) from countries that are “have-nots” in terms of water resources. As another example, Asia has areas with significant water problems, yet exports large quantities of steel that require almost 235,000 liters (62,000 gallons) of water per ton to make.

The UNEP estimates that about 20 percent of total water use is industrial, with the remaining 80 percent divided between agriculture (75 percent) and domestic use (5 percent). A large portion of industrial use is for cooling.

Cooling water is an area of some controversy. Cooling using water has a wide range of applications from nuclear power plant cooling towers to water used directly to cool a product, such as the direct cooling spray used for manufacturing steel. Huge quantities of water are used for cooling, with many applications only resulting in temperature change without contamination. An example would be when river water is used on a flow-through basis to cool boilers. In this scenario, the water flows through the process, only gaining heat, versus evaporative cooling, where the water is changed to vapor and enters the water cycle.

The dilemma is that evaporative cooling works best where there is little humidity, which tends to be those places with water shortages. In the case of flow-through cooling, should the water be considered “blue” or “grey”? Does it count the same as water use where the water cannot be directly reused? This is important where companies are reporting total water use and NGOs and consumers are comparing them.


Industry is not the largest user of water, even though it is common for industry to receive the most attention. The single largest user of water by category is agriculture (estimated at 75 percent by the UNEP). If water is abundant, then there should be little concern. However, there are many areas where irrigation water is withdrawn or diverted from the water table. We all know of instances of dry lakes, sinkholes and other effects of overdrawing the water table. Likewise, there are many rivers where there is increased salt infiltration and low flows as they move from the headwaters to the ocean (e.g., the Colorado River).

Agriculture water use is highly controversial and highly complex. It is well known that agriculture is critical to most underdeveloped countries to feed their population and as a revenue source. Even a highly developed country and region (e.g., California) where water normally is scarce, can be developed into an agricultural utopia, provided you can find water (e.g., San Joaquin Valley). In fact, California is the world's fifth largest supplier of agricultural products due in large part to the ability to move water from water-rich areas to semi-arid areas.

Some have argued that potable water is more important than global warming. It has even been called the “black gold” of the future. What is clear is that there is growing attention paid to water use.

Aside from the “normal” sustainability questionnaires from analysts that go to companies requiring water use information, the Carbon Disclosure Project (CDP) just announced its intent to implement a questionnaire and reporting scheme on water. This is significant as they are the most important common source of information on greenhouse gas reporting, with more than 2,500 companies participating. This will add pressure to companies to establish water use monitoring and conservation measures. This will become even more difficult and complicated with the trend of reporting on environmental metrics for the entire supply chain.

Keep one thing in mind: If water conservation is not on your agenda now, it will be in the future.

Zack Mansdorf, Ph.D., CIH, CSP, QEP, is a consultant in sustainability and EHS. He is a former senior vice president, L'Oreal, and a past president of the American Industrial Hygiene Association. He can be reached at [email protected].

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